Lower abdominal mass on POCUS

Written by: Dr. Callie Winters

Edited by: Dr. Joann Hsu

Case:

An 81-year-old patient presents to the ED from  nursing home with complaint of abdominal distension and hematuria​. The patient was sent in by an outpatient provider to rule out SBO.

  • PE: ​palpable LLQ mass that is nonmobile, tender, nonfluctuant, with no overlying skin changes

    • (+) chronic indwelling foley w/ blood at theurethral meatus​

  • Rest of exam unremarkable

You place your probe on the palpable mass:

You see a very large, complex mass. No obvious bowel or peristalsis. You can see a glimpse of the bladder at the farfield.

Here it is from another axis.

Here is the same mass with external pressure from the probe, to see if we can elicit any internal movement of contents, like we would see in a fluid filled complex structure such as an abscess. As you see here - there is no internal movement of contents.

There is no significant internal flow in this structure.

Not shown here: bilateral hydronephrosis on bedside ultrasound.

Distinguishing solid masses from other structures on POCUS

Is it an abscess?

An abscess could have:

  • Anechoic/hypoechoic areas​

    • Though unlike a simple cyst, may containhyperechoic debris​

  • Swirling of internal debris w/ compression"pusastalsis"​

  • *maybe* septations​

  • Could have dirty shadowing/air​

  • Increased posterior acoustic enhacement​ as is found in a fluid filled structure

  • Encasement/defined rind​ or “contained”

  • Surroundingcellulitis/edema/cobblestoning​

  • Systemic signs/symptoms of infection​, clinical correlation is important!!

An abscess should not have:

  • Significant internal vascularity (color flow)​

  • The appearance of complex, fixed, solid structure - can be hard to differentiate

Is it bowel?

Bowel could have:

  • Peristalsis (withoutcompression)​

  • If SBO:

    • to-and-fro or potentially absent peristalsis​

    • Plicae circulares/keyboard sign visible

    • Dilated loop of small bowel greater than or equal to 2.5 mm

  • Air + fluid​

  • Plicae circulares (SB) orhaustra (LB)​

  • Continuity w/ rest of bowel​

Bowel should not have:

  • Internal septations/complexinternal structure​

  • It should be poop in there​

  • Internal vascular flow

Could it be a solid soft tissue mass?

A soft tissue mass could have:

  • Complex/hyperechoic/mixedechogenic internal structure​

  • May resemble functional solid organ tissue​

  • Internal vascular Flow​

  • Well circumscribed borders

A soft tissue mass should not have:

  • Significant compressibility​ or fluctuance

  • No “swirl sign” - when liquid internal contents swirl during compression as is seen in an abscess

  • Peristalsis​

  • Bowel loops or stool​

​

Prostatic Leiomyomata

  • A rare benign tumor of the prostate gland​

  • 2023 case report cited fewer than 50 cases ever reported​

  • Diagnosed via histology ​

  • Must be distinguished from malignancy​

  • Can present with urinary retention​

  • Well-circumscribed, non-invasive, with amultiloculated, cystic cut surface​

  • Treatment options:​

    • Surgical excision: prostatectomy,transurethral resection​

    • Prostatic artery embolization, observation ifasymptomatic​

Case conclusion:

  • CTAP revealed:​

    • foley balloon malpositioning in the prostatic urethra​

    • 18.5 cm pelvic mass (increased size from prior)​

    • bilateral hydronephrosis​

  • Admitted for AKI​

  • Patient refused surgery for leiomyoma​

  • AKI improved following foley replacement​

  • Discharged back to nursing home after one week in hospital​

Takeaways

  • In rare cases, male urinary retention canbe due to prostatic leiomyomata rather than simple BPH​

  • Treatable, benign tumors​

  • Dx=histology -> must be differentiated from malignancy​

  • To differentiate solid masses from other structures​

  • Use compression​

  • Use color-flow​

  • Use common sense: don't needle aspirate/I+D if unsure​

Happy scanning!

References:

Booth EM